Both Amazon (http://kdp.amazon.com/) and Apple's iBookstore (http://itunes.com/sellyourbooks) have self-publishing options, though if she has a large enough blog or Twitter following, she should try to sell directly from her own site.

Also check out eBookBurn (http://ebookburn.com/) as a resource (it's a service run by my startup, and most of my users are independent authors).

As for tips on composition and content, here is an interesting post from earlier today: "Practical Tips on Writing a Book from 23 Brilliant Authors" http://blogs.plos.org/neurotribes/2011/06/02/practical-tips-...